This application relates to techniques, apparatus and systems that use optical waveguides to deliver light in endoscopes and other instrument for medical, biological, chemical and other applications.
Light can be guided through a light pipe or optical waveguide such as optic fiber to a target to obtain optical images, optical measurements and other operations of the target. The optical waveguide such as optic fiber can be used to reach the target at a location that is otherwise difficult to reach or requires some preparatory procedures to make the target more accessible. For example, the tissue of an internal organ of a patient may be made available for a medical examination or therapy procedure through a natural orifice or an incision to expose the internal organ. Such a procedure may be performed by delivering probe light to the tissue via an endoscope instrument or catheter to reduce or minimize the degree of invasiveness. At the distal end of the instrument, light is pointed to certain direction or steered to interact with an area or a slice of tissue of interest. Delivery of light via an optical waveguide can be implemented to perform various procedures, such as medical imaging, diffuse-reflection spectroscopy, fluorescence spectroscopy, coherence-gated optical tomography, photodynamic therapy, laser hyperthermia and others.
In the above and other procedures that direct light to a target issue, the light beam at the distal end of an endoscope instrument or catheter may be scanned to change the direction of the light beam and, in some procedures, it may be desirable to scan the light beam in more than one trajectory on the target tissue. Scanning of the light beam can be technically difficult because of various limitations in such applications imposed by locations, conditions, geometries, dimensions, or a combination of two or more of these and other factors associated with the target tissue. For example, in some procedures performed in vascular and pulmonary organs, the size of the channels, for instance, blood vessels or bronchus, may limit the dimensions of the instrument to sub-millimeters in their cross-sections and thus present a considerable challenge to designs of beam pointing or steering mechanisms.